A variety of methods have been used in the past to provide movement of a switch actuator such as a button or the like with a tactile feel. A tactile feel has historically been provided by engaging the actuator with a biasing member that imparts a singular biasing force against the actuator that is operative to first increasingly resist and then decreasingly resist movement of the actuator between two positions such as in commonly known snap action type switches.
Examples of a single pair of apposed spring leaves that first resist and then snap to provide a singular biasing force tnat assists in moving an electrical switch between two positions are respectively disclosed in U.S. Pat. Nos. 3,566,057; 3,983,351; and 3,999,025, the disclosures of which are incorporated herein by reference. An example of a double throw type snap action switch that utilizes a dome shaped biasing member to provide a singular biasing force that by reversing direction first resists and then snaps to assist movement of the switch is disclosed in U.S. Pat. Nos. 4,438,304, the disclosure of which is incorporated herein by reference.
As previously described, prior-art biasing members have been limited to providing a singular snap action for imparting a tactile feel to the operation of a switch or the like that is generally coarse in nature.
In contrast to the above, the biasing member of the present invention is operative to provide a more subtle and tactile feel in moving an actuator between two positions by imparting a combination of two biasing forces against the actuator respectively initially increasingly and thence decreasingly apposing movement of the actuator between two positions to provide a tactile feel to its operation.